Hyperventilation happens when PCO2 drops. When PCO2 drops, we become more basic, and pH increases. This means we are alkaline, and that translates to us having respiratory alkalosis. An example of this happening is when we are at high altitude. When we are hypoventilating, we’re breathing too little. We have increased PCO2, and this lowers pH, and makes us more acidic. Therefore, we have respiratory acidosis.
Other pH imbalances include metabolic acidosis, where the production of blood acids exceeds loss. Examples of this include ketoacidosis, diarrhea and intense exercise. On the other hand, metabolic alkalosis is when the production of blood acids is less than loss. An example of this is throwing up.